You may not have read the patent carefully enough (or gotten past the 80-ish pages of drawings). What the patent is actual claiming is a way of getting higher resolution out of stereolithographic materials by blending cross-sectional layers that have a resolution greater than that of the material. By using the claimed method of blending those layers and their cure times in just the right way, you can get thinner (higher-resolution) cross-sectional layers than the material, would get alone.

It was a novel and non-obvious advance in stereolithographic techniques.

You may not have read the patent carefully enough (or gotten past the 80-ish pages of drawings). What the patent is actual claiming is a way of getting higher resolution out of stereolithographic materials by blending cross-sectional layers that have a resolution greater than that of the material. By using the claimed method of blending those layers and varying the cure exposure times in just the right way, you can get thinner (higher-resolution) cross-sectional layers than the material, if cured using normal layer-by-layer techniques, would get alone.

It was a novel and non-obvious advance in stereolithographic techniques.

Although it's not nice of them to sue without talking to the From1 builders first

Since the 2007 MedImmune v. Genentech [wikipedia.org] case it has been very difficult for a patentee to discuss potential infringement or licensing with another party without creating declaratory judgment jurisdiction [wikipedia.org]. DJ jurisdiction allows the alleged infringer to file a suit for a declaratory judgment that the patent is invalid, unenforceable, or uninfringed (or some combination). The big advantage is that it lets the alleged infringer pick the time and place of the suit. So patentees have become more likely to file suit and talk about settlement later rather than trying to negotiate a license and then filing a suit only if that fails.

To be honest, 3d systems is the microsoft of the 3d printing community, they've been buying everybody out, even the small guys who make diy printers, and buying up all the patents. I'm going to guess that Formlabs refused to be bought up into 3D systems borganism, so they're suing them.

3d systems also does other evil things like charging lots for ink(should I call it toner instead?) and punish you if you use any ink that isn't from them. This is especially troublesome when you're using specialty inks to make real parts where you need special properties like fire resistance, something that 3d systems more often than not doesn't offer. Lately they've been trying to push this new cartridge system that uses RFID to make sure you're only using their cartridges. Luckily, it's not catching on.

Thank you, Humpty Dumpty, but words do not mean whatever you want them to mean. You have illustrated their likely strategy, but this does not make them "patent trolls". "Patent troll" means something else:

Patent troll is a pejorative term used for a person or company who enforces patents against one or more alleged infringers in a manner considered aggressive or opportunistic with no intention to manufacture or market the patented invention.